U4初步使用整理（三）Actor基本操作

场景中所有可操作的物件都是基于actor，类似unity的game object.
关键方法：
GetActorLocation()
GetActorScale()
Tick做actor每帧逻辑操作

    // Called every frame
    void AFloatingActor::Tick( float DeltaTime )
    {
        Super::Tick( DeltaTime );
        FVector newPos = GetActorLocation();
        float delatMove = FMath::Sin(RunningTime + DeltaTime) - FMath::Sin(DeltaTime);
        newPos.Z += delatMove * 3;
        SetActorLocation(newPos);

        FVector newScale = GetActorScale();
        newScale.Z = FMath::Sin(RunningTime + DeltaTime) - FMath::Sin(DeltaTime);
        SetActorScale3D(newScale);

        RunningTime += DeltaTime;

    }

FMath::Sin(RunningTime + DeltaTime) - FMath::Sin(DeltaTime)实现了重力效果运动。